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Q: I’ve used lava rock in my filter for years. Are bioballs really that much better?

Dana – Altadena, CA

A: The media you use in your filtration system matters. Just think about its purpose: To house billions of beneficial bacteria and other microorganisms that keep your pond alive, crystal clear and algae-free. Thanks to their ample surface area, both lava rock and bioballs will work, but bioballs have some benefits over the rock. Read on to learn more.

Lava Rock’s Limitations

Lava rock – that igneous rock that’s formed as an erupting volcano’s molten lava cools and hardens – is very porous. When chunks of it live in your filtration system, you’re providing a lot of surface area for those beneficial bacteria to colonize and grow. That’s what makes it such a great filter media.

It does, however, have its drawbacks.

Clogged Holes: Over time, the porous rock can become easily clogged with muck and debris. Once the holes and pockets are clogged, they can become very difficult to clean out – which ultimately creates less overall surface area.

Hard Water: Lava rock naturally contains a variety of minerals, including iron and magnesium, that could affect your water’s pH, making it harder. Hard water could make it more difficult to treat algae that forms.

It’s Heavy!: They may be porous chunks of rock, but hefting bags of it takes some strength – particularly when its wet and full of gunk.

Benefits of BioBalls

Bioballs, like The Pond Guy® BioBalls™ filter media, are plastic spheres made up of dozens of thin rods that provide plenty of surface area for beneficial bacteria to thrive. Two hundred of the bioballs in a mesh bag will filter about 1,000 gallons of water in a pond with minimal fish.

Compared to lava rock, bioballs have some definite benefits.

Easy to Clean: Bioballs can also become clogged, by they’re easy to clean. Just rinse them off with water from your pond and you’ll be good to go.

Indefinite Lifetime: Because they’re made from long-lasting material, bioballs will not degrade and will function equally well year after year.

Shape Shifters: The bioballs’ round shape allows them to more easily conform to any filter, no matter its shape.

Lightweight, Easy to Handle: Each one of these tiny, 1 1/2-inch plastic spheres weighs a scant 0.3 ounces; 200 of them weigh a whopping 3 1/2 pounds. They’re easy to deposit and remove from your filter thanks to a mesh filter bag.

Consider making the switch from lava rock to bioballs. You’ll see better results and you’ll need to do less maintenance. What’s better than that?

I’ve always been told to use lava rock in my waterfall filter, is this the best media to use?
Tara – Bon Temps, LA

Lava rock was a common form of biological filtration media in waterfall boxes as its porous surface provides room for bacteria to reside. While it was popular years ago, pond supply companies have since produced better forms of secondary biological filtration media that are friendlier for both you and the pond itself.

Using lava rock as a source of filtration media has a list of distinctive drawbacks. The first of which is that it can prove to be extremely heavy and cumbersome. It is not exactly easy to lift a bag of rocks out of your pond, especially when it is full of water and debris.
While lava rock is porous and can initially provide a reasonable amount of additional surface area, the coarseness and small opening sizes tend to hold on to passing-by debris, blocking the waterways which greatly diminishes the stone’s performance. Once lava rock is loaded with debris you will have to remove it form your filter box and replace it with new media as it is near impossible to remove the debris from within each rock. For some pond owners this means they would need to replace their lava rock media multiple times each season for optimal performance. Furthermore lava rock tends to be brittle and can leave behind additional dust and debris in your pond.

Biological filtration media like BioBalls™ filter media provides all of the surface area that your beneficial bacteria desire but implement it into a light-weight cost-effective design. One of the best qualities of secondary filtration media like the BioBalls™ is that you only have to buy them once. The Pond Guy® BioBalls™ do not degrade over time and can simply be rinsed out at the end of the season and reused the next. BioBalls™ can placed into a mesh media bag and can be placed right into your waterfall filter box.

Pond Talk: Have you used lava rock as filter media in the past and switched to bio balls or another form of media? Did you notice a difference in filtration performance?